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( u B. M. HAMILTON.

' ELECTRIC TELEGRAPH TRANSMITTER.

No. 269,521. Patented Dec. 26, 1882.

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UNITED STATES PATENT Fries.

EMERY M. HAMILTON, OF NEW YORK, N.-Y.

ELECTRIC TELEGRAPH TRANSMITTER.

SPECIFICATION forming part of Letters Patent No. 269,521 dated December 26, 1882.

To all whom it may concern:

Be it known that I, EMERY M. HAMILTON, of the city, county, and State of New York, have invented certain new and useful Improvements in Electric Telegraph Transmitters or other Analogous Electrical Instruments, of whichthe following is a specification, reference being had to the accompanying drawings, forming part of the same.

The invention relates to electric telegraph transmitters or other analogous electrical instruments, and particularly to the lever or bar therein that is intended to vibrate, in conjunction. with the breaking and closing of the electric circuit, in the operation of telegraphing; and it consists in the peculiar construction and arrangement of said lever in its relation to the breaking and closing of the circuit, as hereinafter described and claimed.

In the drawings I have shown my invention as applied to the common telegraph-key.

Figure 1 is a plan or top View of a key containing my invention. Fig. 2 is a side elevation. Fig. 3 is a central vertical section of the same, and Fig. 4 shows a detached part of the side elevation; r

A is the base plate or bar.

B B are two screw posts or bolts, by which the instrument is secured to the table, and with which the line-wires are connected; The post B is insulated from the plate A by suitable insnlating material, a, between the head I) of said post and the sides of the openingin A through which B passes, as shown plainly in Fig. 3. c c are the usual platinum contactpoints.

O is the vibrating lever, by the movement of which the circuit;- is broken and closed in a transmitter. The hinge or joint upon which the lever vibrates is formed of a projection or rib, 0, extending across the upper face of "the lever, which fits into a corresponding groove or channel, 0, made in the under face of a fixed overhanging flange or bar, 6 which may be fixed and supported in itsposition by any suitable means. In the drawings it is represented as a flange projecting horizontally from the top of the abutment f, formed or secured on the base-plate A. The sides of the groove 0 converge to form an angle at the bottom, and the rib e is formed to fit into and rock in the Application filed March 2'3, 1882. (No model.)

groove as the lever is vibrated. This rib is preferably triangular in form, and is proportioned so that its upper edge or angle will fit into the groove so as to permit no lateral jar or movement, and whereby the lever will be caused to always vibrate in precisely the same plane. To this end the angle of the groove must be sufficiently small to prevent the said rib from sliding upward on the sides of the groove by any side thrust or pressure on the opposite vibrating end of the lever under the hand of the operator, and the angle of the rib must of course be somewhat less than that of the groove-to permit it to rock therein. The rib e and groove 6 may be reversed-that is to say, the groove may be made in the lever and the rib be formed on or secured to the flange e I have thus described what I regard as the best form of a pivotal jointin the vibratinglerib is pressed into the groove by a spring or its equivalent, while the lever is free to rock or vibrate on its pivot, a tight joint shall be maintained and all rattlingand shaking ortreinbling of the lever on its pivot shall be prevented. Lateral motion or shifting of the lever in its seat may be prevented by a stud or pin projecting from the innert'ace of the ledgef, that enters a slot or notch in the end of the lever, as indicated by dotted lines at h in Figs. 1 and D is a set-screw that works in a threaded aperture through the lever 0, near its pivotal end. This screwis hollow or recessed, as shown plainly in Fig. 3. k is a spiral spring placed in the said screw, its lower end resting on the plate A. This spring acts to swing the lever upward, and at the same time to press the parts forming the pivotal hinge into firin and steady contact.

The tension of the spring may be varied and adjusted by turning the screw D in or out. The long leverage thus secured permits the use of a very stiff quick-acting spring, while it enables the lever to be vibrated with exceeding ease and precision.

acts to force the parts into contact.

I am aware that a similar spiral spring fora similar purpose in a transmitter has had the upper eml of the wire of which the spring has been formed straightened and set in a small socket or hole in the end of a set-screw connectcd with the lever, as shown in the United States Patent No. 232,007, issued to Patrick E. Delany, September 7,1660; but the placing of the end of the wire in such a hole or socket, as shown in said patent, is merely for the purpose of preventing the slipping of the upper end of the spring out of adjustment with the lever. I disclaim such device, and limit my claim to the combination of the set-screw D and the spring lc,when the said set-screw is recessed, so as to receive the body of the spiral spring within the recess, thereby permitting the base A and the lever G to be placed near together, and yet a spring to be used of sufficient length to have the requisite resistance and resiliency.

E is a set-screw at the opposite or vibrating end of the lever. The head (I of this screw constitutes the button or finger-piece of the lever. The lower end is provided with a small button or disk, (1, which takes under a projection, (1 in the end of the plate A. This serves to limit the upward movement of the lever. By turning the screw down the move ment is enlarged, and by turning it back it is decreased. This construction and arrangement of parts enables the operator to adjust the distance of vibration of the lever very convenientlyand without removing his finger from the button.

F is the switch for closing the circuit when not operating. The head of the screw D, the button (I, and the handle 2' of the switch are all made of or covered by rubber or equivalent non-conducting material, so that the operator will not in operating or adjusting the key have to touch any part that is a conductor of electricity. A short upwardly-projeeting stud near the end of the base-plate A, provided with a projecting disk or flange on its upper end for engagement with the disk or flange cl, would be the equivalent of the projection d.

The arrangement and relative position of the several parts I have described and shown are essential to the operation of the instrument as intended. The hinge on which the lever vibrates must be formed and arranged, as described, so that the parts are forced into contact by an upward pressure, or in the direction opposite to that of the hand or finger of the operator when pressing the lever to close the circuit. Then, as it is obvious, such pressure will cooperate with the spring that This permits the break-circuit points to be placed intermediate the pivotaljoint and the vibrating or button end of the lever, thus obviating by a slight yielding or spring-like action of the lever the solid anvil-like resistance of the contact-points,sodisagreeableto the operatorwhen such points areimmediately under his hand,and giving the advantageof leverage in pressing thepoiutsinto contact. When the pivotaljoint is placed underneath the lever, and the parts are forced into contact by the downward pressure ofa spring, as in the English Letters PatentNo. 2,525 of A. D. 1869, it is necessary to place the break-circuit points under the hand of the operator, or at the finger or button end of the lever, as, if placed intermediate the ends of the lever, such pointsacting as a fulcrum, the tendency of the hand of the operator at every downward movement must be to rock the lever on such fulcrum and throw the pivotal end upward and out of contact with the lower part of the joint. I disclaim all that is set forth in the English patent referred to.

It is also important, in order that there may be the least possible resistance to the vibration of the lever from its own inertia, that the pivotal joint should he as near as may be in the plane of the longitudinal axis of the lever, as it is shown in the drawings. If the pivotal line or point is above or below such plane, then, as is obvious, the entire lever will rock on the are of a circle whose radius is equal to the distance from the pivotal line or point to the said plane of the lever. Under these circumstances the resistance to vibration resulting from the inertia of the lever would be considerable, and just tothe extentthatits inertiais encountered would the ease and delicacy of its movement be diminished. In the English Patent No.

' 2,525 of 1869, before referred to, the objectionable feature here pointed out appears, which,

. as I have indicated, is remedied by locating,

as I do, the pivotal point or line in or very nearly in the plane of the longitudinal axis of the lever. A

What I claim as my invention, and desire to secure by Letters Patent, is

1. In a telegraphtransmitter, the lever C, the pivotal joint of which is composed ofthe upwardly-projecting rib e and the corresponding groove or channel, 0, in the nnder side of the ledge or plate e together with the spring 70, located underneath the said lever near its pivotal joint, and between the said joint and the break-circuit points 0 c, the said points being located between the said spring and the button or tree end of the lever, all arranged and combined to operate as and for the purpose described.

2. In a telegraph-transmitter, the lever C, the pivotal joint of which is composed of the rib e and the corresponding groove, 0, the pivotal line of the said joint being in or nearly in the coiled body or" which is located in said rebase-plate A, provided with the projection d cess. all combined and arranged substantially of the adjustable set-screw E, provided with as and for the purpose described. the disk (1 and the button at, as'and for the 4. The combination, with the lever G and purpose described.

5 base-plate A, of the adjustable setscrew E, Witness my hand this 17th day of March, 15

provided at its lower end with a disk, d, con- A. D. 1882. structed and arranged to engage with the un- EMERY M. HAMILTON. der side ofthe projection d, as and for thepur- In presence ofpose described. A. G. W. VERMILYE,

10 5. The combination, with the lever (l and GEO. W. BEEBEE. 

